But why invest the money and engineering to create these "clean" ICE vehicles then long-term FCEV or rapid-charging BEVs make more sense and require far less exotic technologies such as HCCI. Not to mention how much mechanically simpler electric cars are, usually you can count the number of moving propulsion parts on one hand. Especially since assuming you're using Nuclear, geothermal, wind, etc to generate the electricity means it will be far cheaper to operate. Even now the actual cost to operate a BEV is far lower than to fuel a gasoline vehicle. I think until there is a wind-change miracle technology there will still be a place for ICE vehicles, especially in air travel since the amount of energy needed is extremely hard to get in any other way in a form lightweight enough to be useful.